#aaa{
	height: 800px;
	background-color: rgba(0,0,255,0.2);
	background-image: url(../images/testji.png);
	background-repeat: no-repeat;
	background-position: center;
	/* background-position: right bottom; */
	background-attachment: fixed;
	/* 覆盖整个背景，最大边为准 */
	background-size: cover;
	/* 包含图片，最小边为准*/
	background-size: contain;
	
	color: brown;
	/* 让文字从右到左显示
	direction: rtl;
	unicode-bidi: bidi-override;
	*/
   line-height: 800px;
   text-align: center;
   /* 字符间距 */
   letter-spacing: 20px;
	/* 字间距,针对英文的单词之间的间距 */
	word-spacing: 20px;
	/* 空白的处理(换行也是空白) */
	white-space: normal;
	text-decoration: line-through;
}
#bbb{
	height: 500px;
	background-image: url(../images/dcent.png);
	background-repeat: no-repeat;
	background-position: -400px -100px;
}

/*********** 简单特效作业css **********************/
.ab{
	width: 80px;
	height: 50px;
	background-color: antiquewhite;
	line-height:50px ;
	text-align: center;
}
.aba{
	width: 100%;
	height: 5px;
	background-color: aqua;
}
.ab:hover .aba{
	background-color: black;
}
.ab:active{
	background-color: red;
}